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Flashcards in Specialised cells and stem cells Deck (42)
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1

Outline the levels of organisation of a multicellular organism (in order).

Organelle ---> cell ----> tissue ---> organ ----> organ system ----> organism.

2

Define the term “specialised”.

Having a particular structure to serve a specific function.

3

Define the term ''differentiation''.

The process of a cell becoming differentiated. Involves the selective expression of genes in a cell's genome.

4

Explain why multicellular organisms have specialised cells.

Because multicellular organisms have many different complex processes taking place constantly. As a result, some cells need to have a specific structure that allows them to carry out a specific function effectively.

5

Draw label and annotate diagrams to show how erythrocytes are specialised for their function.

Function: Carry oxygen in blood.
- Biconcave disc shape which provides a large SA for gas exchange.
- They have no nucleus and very few organelle. This increases the space available for haemoglobin.
- They are flexible so they can squeeze through narrow capillaries.

6

Draw label and annotate diagrams to show how neutrophils are specialised for their function.

Function: A type of white blood cell, important part of the immune system.
- They have a flexible shape which allows them to engulf foreign pathogens.
- Multi lobed nucleus that makes it easier for them to squeeze through gaps to get to the site of infections.
- Cytoplasm contains many lysosomes which break down the engulfed particles.

7

Draw label and annotate diagrams to show how sperm cells are specialised for their function

Function: deliver genetic information to the female gamete.
- Have a flagellum which means they are capable of movement.
- They have lots of mitochondria to provide energy for swimming.
- Acrosome (part of the head) contains digestive enzymes. These are released to digest the protective layers around the ovum, allowing the sperm to penetrate.

8

Draw label and annotate diagrams to show how palisade cells are specialised for their function.

Function: The site of photosynthesis.
- contain many chloroplasts that absorb large amounts of energy for photosynthesis.
- The cells are a rectangular box shape so they can be closely packed to form a continuous layer.
- Have thin cell walls to increase the rate of diffusion of CO2.

9

Draw label and annotate diagrams to show how
root hair cells are specialised for their function.

Function: Absorb mineral ions and water from the soil.
- They have lots of root hairs which are long extensions of the cell and act to increase its SA to maximise uptake of water and mineral ions.
- Thin permeable cell wall for entry of water and ions.
- Cytoplasm contains extra mitochondria to provide the energy needed for active transport.

10

5. Draw label and annotate diagrams to show how guard cells are specialised for their .

Function: Control whether the stomata or opened or closed for the release or entry of gases.
- They are found in pairs with gap between them to form a stoma, this is necessary for CO2 to enter the plant.
- In the light, guard cells take up water into their vacuoles and become turgid.Thin outer walls and thickened inner walls force them to bend outwards, opening the stoma. One side of the cell wall is thicker than the other.
- When they loose water they become less swollen and change shape and the stoma close to prevent further.

11

State the 4 main categories of tissues in animals.

- Nervous tissue which is adapted to support transmission of electrical impulses.
- Epithelial tissue. Adapted to cover body surfaces, internal and external.
- Muscle tissue. Adapted to contract.
- Connective tissue. Adapted either to hold tissues together or as a transport medium.

12

Draw label and annotate diagrams to show how squamous epithelium is specialised for their function (link structure to function using annotations).

- It is made up of specialised squamous epithelial cells.
- Very thin because it contains flat cells.
- Only one cell think.
- Present when rapid diffusion across a surface is essential.
- It forms lining of lungs and allows rapid diffusion of O2 into blood.

13

Draw label and annotate diagrams to show how ciliated epithelium is specialised for their function (link
structure to function using annotations)

- Made of ciliated epithelial cells.
- Have hair-structures called cilia which move in a rhythmic manner.
- They line the trachea and cause mucus to be swept away from the lungs. Goblet cells are present to release mucus to trap unwanted particles, stopping them reaching the lungs.

14

Draw label and annotate diagrams to show how cartilage is specialised for their function (link
structure to function using annotations).

- A connective tissue found in ears, nose, between bones and ends of bones.
- Contains fibres of the proteins elastin and collagen.
- It is a firm flexible connective tissue composed of chondrocyte cells embedded in extra cellular matrix.
- It prevents the ends of bones from rubbing together and causing damage.

15

Draw label and annotate diagrams to show how
muscle is specialised for their function (link
structure to function using annotations).

- Muscles shortens in length in order to move bones which move different parts of the body.
- Skeletal muscle fibres which attach to bone and contain myofibrils which contain contractile proteins.

16

Define the term “cell".

A basic unit of life. Consists of cellular contents surrounded by a plasma membrane. All life is composed of these basic units whether it is unicellular or multi-cellular.

17

Define the term "tissue”.

A collection of differentiated cells that work together to perform a specialised function or functions.

18

Define the term “organ”.

A collection of tissues that work together to perform a particular function in an organism.

19

Define the term “organ system”.

A number of organs working together to carry out a major function in the body.

20

Draw label and annotate diagrams to show how the epidermis of plants are specialised for their function (link structure to function using annotations).

- A single layer of closely packed cells covering the surface of plants.
- Usually covered by a waxy water proof cuticle; this reduces the loss of water.
- Stomata are present in epidermis to allow the exchange of CO2, O2 and water vapour.

21

Draw label and annotate diagrams to show how xylem tissue are specialised for their function (link
structure to function using annotations).

- It transports water and minerals around the plant
- Supports the plant because the walls of the xylem vessels are strengthened with water proof lignin which provides structural support for the plants.
- Contains hollow xylem vessels which are elongated dead cells.
- Also contains living parenchyma cells, these fill in the gap between xylem vessels.

22

Draw label and annotate diagrams to show how phloem tissues are specialised for their function.

- Transports organic nutrients like sucrose from leaves and stems to everywhere.
- Composed of columns of sieve tube cells separated by perforated walls called sieve plates. These allow sap to move easily between cells.
- Substances can move easily through the sieve tube element because they have very little cytoplasm. They also have very thin walls.
- They also have companion cells (linked to the sieve tube by plasmodesmata) which perform all the cellular reactions of the sieve tube i.e. they have lots of mitochondria to provide ATP for the sieve.

23

State 3 examples of organ systems in animals and for each describe their function.

- Digestive system; breaks down large insoluble molecules to small soluble ones, absorbs nutrients into blood, retains water, removes undigested material.
- Cardiovascular system; moves blood around the body.
- Gaseous exchange system; brings air into the body so oxygen can be extracted for respiration.

24

Define stem cell.

Undifferentiated cells with the potential to differentiate into a variety of the specialised cell types of the organism.

25

Define undifferentiated cell.

An unspecialised cell originating from mitosis or meiosis.

26

Define totipotent.

A stem cell that can differentiate into any type of cell and form a whole organism.

27

Define pluripotent.

A stem cell that can differentiate into any type of cell but not form a whole organism.

28

Define multipotent.

A stem cell that can only differentiate into a range of cell types within a certain type of tissue.

29

Define embryonic stem cell.

A stem cell found within embryos. Zygotes and the cells of the very early embryos are totipotent. When the embryo has developed into the blastocyst (a mass of cells) they are now pluripotent. They remain like this until a few days before birth.

30

Define tissue stem cell.

They are found in specific areas e.g. bone marrow. They are multipotent but might be able to be artificially triggered to become pluripotent.
They are how specialised tissues replace cells. (They can be harvested from umbilical cords.)